Exemplary embodiments of the invention relate to a device for adjusting a motor vehicle valve train.
German patent document DE 10 2005 006 489 A1 discloses a device for adjusting a motor vehicle valve train, having at least one camshaft which includes at least four cam elements arranged in an axially displaceable manner.
Exemplary embodiments of the present invention are directed to a particularly advantageous variable device for adjusting a motor vehicle valve train. Specifically, exemplary embodiments of the invention are directed to a device for adjusting a motor vehicle valve train, having at least one camshaft which includes at least four cam elements arranged in an axially displaceable manner.
In accordance with the invention in each case two of the cam elements that are adjacently situated are formed as a cam element group to be switched together. The cam elements may thus be switched in a particularly advantageous manner, and in particular the device for adjusting a motor vehicle valve train may have a particularly variable design. A “camshaft” is understood in particular to mean a shaft that is provided for activating multiple valves of an internal combustion engine and for activating one valve of at least one cam track in each case. It is also conceivable for the camshaft to be designed as an intake camshaft and provided for activating intake valves, or also for the camshaft to be designed as an exhaust camshaft and provided for activating exhaust valves. A “cam element” is understood in particular to mean an element mounted on a camshaft in a rotationally fixed manner, and which, for activating a valve, is provided for directly or indirectly acting on the valve in question with at least one lift. The term “in a rotationally fixed manner” is understood in particular to mean a connection that transmits a torque and/or a rotational motion unchanged. The term “axial” is understood in particular to mean axial in relation to a main axis of rotation of the cam element. The term “axially displaceable” is understood in particular to mean that the cam element is displaceable on the camshaft, parallel to the main axis of rotation of the cam element, between at least two switching positions. In the present context, the term “adjacently situated” is understood in particular to mean that the cam elements adjoin one another in the axial direction, and in particular no element, in particular no other cam element, is located between the adjacently situated cam elements. A “cam element group” is understood in particular to mean a grouping of two cam elements which are switchable together, the two cam elements being designed as two separate, independently formed components. The cam elements of a cam element group are in particular movable relative to one another in the axial direction of the camshaft in at least one operating state. The term “to be switched together” is understood in particular to mean that the two cam elements are always switched together by means of an activation, whereby an actual axial displacement of the cam elements may take place in a staggered manner.
It is further disclosed that the two cam element groups are switchable independently of one another. The cam elements may thus be switched in a particularly advantageous manner, and the device for adjusting a motor vehicle valve train may have a particularly variable design. The term “switchable independently of one another” is understood in particular to mean that a cam element group remains uninfluenced by switching of another cam element group.
It is further disclosed that the device for adjusting a motor vehicle valve train has an actuator device that in each case is associated with one of the cam element groups and which couples the two particular cam elements of the cam element group to one another during a switchover operation. The two cam element groups may thus be switched independently of one another in a particularly simple manner. An “actuator device” is understood in particular to mean a device that provides a force for switching the cam elements in order to switch the cam elements from one switching position into another switching position, and for this purpose the cam elements preferably have at least one actuator. The term “couple” is understood in particular to mean that in the switchover operation, the two cam elements of a cam element group undergo a defined movement with respect to one another due to engagement of the actuator device, and/or that a switching element of the actuator device, in particular a switch pin, is guided by a gate track of one of the cam elements directly into a gate track of the other cam element.
It is further disclosed that the two cam element groups are provided for activating valves of a four-cylinder in-line engine or of one line of an eight-cylinder V engine. The activation of valves of a four-cylinder in-line engine may thus take place in a particularly advantageous manner.
In addition, it is disclosed that the device for adjusting a motor vehicle valve train has a third cam element group, the three cam element groups being provided for activating valves of a six-cylinder in-line engine or of one line of a twelve-cylinder V engine. The activation of valves of a six-cylinder in-line engine may thus take place in a particularly advantageous manner.
Furthermore, it is disclosed that the device for adjusting a motor vehicle valve train has a control and/or regulation unit provided for operating, in at least one operating state, two cam elements of one of the cam element groups in a different switching position than the two cam elements of another of the cam element groups. Cylinders associated with the cam elements of the one cam element group may thus advantageously be operated with a different valve lift than the cylinders which are associated with the cam elements of another cam element group. A “control and/or regulation unit” is understood in particular to mean a unit having at least one control device. A “control device” is understood in particular to mean a unit having a processor unit and a memory unit, and having an operating program which is stored in the memory unit. In principle, the control and/or regulation unit may have multiple interconnected control devices which are preferably provided for communicating with one another via a bus system, in particular a CAN bus system. The term “provided” is understood in particular to mean specially programmed, designed, and/or equipped. The term “switching position of a cam element” is understood in particular to mean a defined position of the cam element which the cam element assumes after completion of a switching operation, and in which a defined cam track is engaged with the valve in question. The term “operating a different switching position” is understood in particular to mean that the cam elements of the one cam element group activate the valves associated with them with a valve lift which differs from a valve lift with which the cam elements of the other cam element group activate the valves associated with them. In this regard, the lift height and/or lift characteristic of the valve lifts may be different and/or may start in a staggered manner.
It is further disclosed that in at least one operating state, the control and/or regulation unit is provided for initially switching the cam element group whose first cam element is the next to reach its base circle phase. Switching of the cam elements may thus take place particularly quickly. A “first cam element of a cam element group” is understood in particular to mean the cam element of the two cam elements which are combined to form a cam element group, whose associated cylinder, considered starting from a firing order of the two cylinders associated with the cam elements, has an ignition point which chronologically precedes an ignition point of the cylinder which is associated with the second cam element.
Further advantages result from the following description of the drawings. Two exemplary embodiments of the invention are illustrated in the drawings. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also advantageously consider the features individually and combine them into further meaningful combinations.